64 research outputs found
Análise crítica da construção de uma escola em Guiné-Bissau : vantagens e desvantagens no regime de ajuda mútua
A falta de moradias atinge milhões de pessoas por todo o mundo, apesar de ser um direito básico fundamental a todos os indivíduos. Uma alternativa possível a este problema é a ajuda mútua, na qual uma comunidade une-se em prol da construção de edificações. Em Guiné-Bissau, em 2011, o autor participou da construção de uma escola no regime de ajuda mútua. Este trabalho elenca as vantagens e desvantagens encontradas na experiência africana, possibilitando uma análise crítica desta forma construtiva pouco abordada na literatura, através de uma comparação do que temos na bibliografia e apresentando dificuldades não exploradas até então.The lack of housing strikes millions of people all over the world, despite of being a basic and fundamental right to all people. A possible alternative to this problem is the mutual-aid, in which a community gathers to build edifications. In Guinea-Bissau, in 2011, the author took part in the construction of a school through mutual-aid. This paper brings the advantages and disadvantages found in this African experience and analyses it by comparing data available in literature and showing difficulties unexplored until now
InTreeger:An End-to-End Framework for Integer-Only Decision Tree Inference
Integer quantization has emerged as a critical technique to facilitate deployment on resource-constrained devices. Although they do reduce the complexity of the learning models, their inference performance is often prone to quantization-induced errors. To this end, we introduce InTreeger: an end-to-end framework that takes a training dataset as input, and outputs an architecture-agnostic integer-only C implementation of tree-based machine learning model, without loss of precision. This framework enables anyone, even those without prior experience in machine learning, to generate a highly optimized integer-only classification model that can run on any hardware simply by providing an input dataset and target variable. We evaluated our generated implementations across three different architectures (ARM, x86, and RISC-V), resulting in significant improvements in inference latency. In addition, we show the energy efficiency compared to typical decision tree implementations that rely on floating-point arithmetic. The results underscore the advantages of integer-only inference, making it particularly suitable for energy- and area-constrained devices such as embedded systems and edge computing platforms, while also enabling the execution of decision trees on existing ultra-low power devices
From Ground to Orbit:A Robust and Efficient Test Methodology for RISC-V Soft-Cores
As traditional space-grade computing systems struggle to meet the increasing computational demands of modern space missions, RISC-V emerges as a promising alternative due to its open-source and highly customizable nature. However, the extensive hardware customization options in RISC-V introduce complexity in validation, making it challenging to ensure system reliability. This paper introduces a robust methodology for validating RISC-V-based systems under accelerated radiation beams, focusing on test uptime, leveraging Commercial Off-The-Shelf (COTS) FPGA devices, which offer flexibility and cost-effectiveness, to enable concurrent hardware and software development. We demonstrate how our methodology offers a comprehensive approach for testing heterogeneous systems on FPGAs, balancing thorough integration with cost-efficiency and test robustness. During our experiments with accelerated neutrons to assess the resilience of RISC-V cores, our approach guaranteed the correct delivery of 100% of the packages, while minimizing system downtime during radiation testing by reducing the Test Fixture SEFI cross-section.</p
Design and Experimental Investigation of Trikarenos:A Fault-Tolerant 28nm RISC-V-based SoC
We present a fault-tolerant by-design RISC-V SoC and experimentally assess it under atmospheric neutrons and 200 MeV protons. The dedicated ECC and Triple-Core Lockstep countermeasures correct most errors, guaranteeing a device cross-section lower than cm
Nanoparticles exhibiting self-regulating temperature as innovative agents for Magnetic Fluid Hyperthermia
During the last few years, for therapeutic purposes in oncology, considerable attention has been focused on a method called magnetic fluid hyperthermia (MFH) based on local heating of tumor cells. In this paper, an innovative, promising nanomaterial, M48 composed of iron oxide-based phases has been tested. M48 shows self-regulating temperature due to the observable second order magnetic phase transition from ferromagnetic to paramagnetic state. A specific hydrophilic coating based on both citrate ions and glucose molecules allows high biocompatibility of the nanomaterial in biological matrices and its use in vivo. MFH mediator efficiency is demonstrated in vitro and in vivo in breast cancer cells and tumors, confirming excellent features for biomedical application. The temperature increase, up to the Curie temperature, gives rise to a phase transition from ferromagnetic to paramagnetic state, promoting a shortage of the r2 transversal relaxivity that allows a switch in the contrast in Magnetic Resonance Imaging (MRI). Combining this feature with a competitive high transversal (spin-spin) relaxivity, M48 paves the way for a new class of temperature sensitive T2 relaxing contrast agents. Overall, the results obtained in this study prepare for a more affordable and tunable heating mechanism preventing the damages of the surrounding healthy tissues and, at the same time, allowing monitoring of the temperature reached
Seismic markers of the Messinian salinity crisis in the deep Ionian Basin
We conduct the seismic signal analysis on vintage and recently collected multichannel seismic reflection profiles from the Ionian Basin to characterize the deep basin Messinian evaporites. These evaporites were deposited in deep and marginal Mediterranean sedimentary basins as a consequence of the “salinity crisis” between 5.97 and 5.33 Ma, a basin‐wide oceanographic and ecological crisis whose origin remains poorly understood. The seismic markers of the Messinian evaporites in the deep Mediterranean basins can be divided in two end‐members, one of which is the typical “trilogy” of gypsum and clastics (Lower Unit – LU), halite (Mobile Unit – MU) and upper anhydrite and marl layers (Upper Unit – UU) traced in the Western Mediterranean Basins. The other end‐member is a single MU unit subdivided in seven sub‐units by clastic interlayers located in the Levant Basin. The causes of these different seismic expressions of the Messinian salinity crisis (MSC) appear to be related to a morphological separation between the two basins by the structural regional sill of the Sicily Channel. With the aid of velocity analyses and seismic imaging via prestack migration in time and depth domains, we define for the first time the seismic signature of the Messinian evaporites in the deep Ionian Basin, which differs from the known end‐members. In addition, we identify different evaporitic depositional settings suggesting a laterally discontinuous deposition. With the information gathered we quantify the volume of evaporitic deposits in the deep Ionian Basin as 500,000 km3 ± 10%. This figure allows us to speculate that the total volume of salts in the Mediterranean basin is larger than commonly assumed. Different depositional units in the Ionian Basin suggest that during the MSC it was separated from the Western Mediterranean by physical thresholds, from the Po Plain/Northern Adriatic Basin, and the Levant Basin, likely reflecting different hydrological and climatic conditions. Finally, the evidence of erosional surfaces and V‐shaped valleys at the top of the MSC unit, together with sharp evaporites pinch out on evaporite‐free pre‐Messinian structural highs, suggest an extreme Messinian Stage 3 base level draw down in the Ionian Basin. Such evidence should be carefully evaluated in the light of Messinian and post‐Messinian vertical crustal movements in the area. The results of this study demonstrates the importance of extracting from seismic data the Messinian paleotopography, the paleomorphology and the detailed stratal architecture in the in order to advance in the understanding of the deep basins Messinian depositional environments.
Highlights
First description of a new type of deepwater Messinian salt giant in the Ionian Sea.
First quantification of the Messinian salt volume in the Ionian Sea.
New seismic evidence of erosional surfces and Lago Mare deposits in the deep Ionian Basin.
Further evidence of sea level lowering during the Messinian Salinity Crisis.
Evidence for a different, physically separated deepwater Messinian salt basins in the Mediterranean
Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study
Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world.
Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231.
Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001).
Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication
Comparación de modelos no lineales para describir curvas de crecimiento del portainjerto limón rugoso (Citrus jambhiri Lush.) bajo condiciones de vivero
This work aimed to find the statistical model that best describes the growth pattern of Lemon 'Rugoso' rootstock (Citrus jambhir Lusch.) in the nursery up to grafting diameter. Thus, the sowing was carried out in seedlings. 45 days after emerging, the seedlings were transplanted to 5 L pots with a substrate consisting of rice husks (40%), soil (40%), and commercial substrate (20%). Growth variables were evaluated every 30 days. For aerial growth, the following were quantified: neck diameter (DC), number of leaves (CH), stem length (LT), fresh mass of the stem (MFTa), fresh mass of leaves (MFH), dry mass of the stem (MSTa), dry mass of leaves (MSH). Also, root growth through root length (LR), fresh (MFR) and dry root mass (MSR), and total variables: total fresh mass (MFTotal), total dry mass (MSTotal), and full length (LT). To model growth curves, Logistic, Gompertz, and Monomolecular models were tested. The Gompertz model best fitted the rootstock growth over time for the aerial growth variables (except the number of leaves) and for the total variables (except the total length), while the Logistic model was the one that best adjusted the growth of the rootstock based on the time for the root growth variables. It was also suitable for the variables number of leaves and total length due to it presented a lower residual mean square of the error compared to the Logistic, Richards, and Monomolecular models. El objetivo fue encontrar el modelo estadístico que mejor describa el patrón de crecimiento del portainjerto Limón 'Rugoso' (Citrus jambhiri Lusch.) en vivero hasta diámetro de injertación. Para ello se sembró en almácigos y a los 45 días de la emergencia los plantines se trasplantaron a macetas de 5 L con sustrato constituido por cascarilla de arroz (40 %), suelo (40 %), y sustrato comercial (20 %). Se evaluaron variables de crecimiento cada 30 días. Para el crecimiento aéreo se cuantificó: diámetro de cuello (DC); cantidad de hojas (CH), largo del tallo (LT); masa fresca del tallo (MFTa), masa fresca de hojas (MFH), masa seca del tallo (MSTa); masa seca de hojas (MSH). También el crecimiento de raíz mediante: largo de raíz (LR), masa fresca (MFR) y seca de raíz (MSR), y variables totales: masa fresca total (MFTotal); masa seca total (MSTotal) y largo total (LT). Para modelar las curvas de crecimiento se probaron los modelos Logístico, Gompertz y Monomolecular. El modelo Gompertz fue el que mejor ajustó al crecimiento del portainjerto en el tiempo para las variables de crecimiento aéreo (a excepción del número de hojas) y para las variables totales (a excepción del largo total), mientras que el modelo Logístico fue el que mejor ajustó al crecimiento del portainjerto en función del tiempo para las variables de crecimiento radicular. También, obtuvo buen ajuste para las variables número de hojas y largo total, debido a que presentó menor cuadrado medio residual del error comparado con los modelos Logístico, Richards y Monomolecular
Pooled analysis of who surgical safety checklist use and mortality after emergency laparotomy
Background: The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods: In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results: Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89⋅6 per cent) compared with that in countries with a middle (753 of 1242, 60⋅6 per cent; odds ratio (OR) 0⋅17, 95 per cent c.i. 0⋅14 to 0⋅21, P < 0⋅001) or low (363 of 860, 42⋅2 percent; OR 0⋅08, 0⋅07 to 0⋅10, P < 0⋅001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference −9⋅4 (95 per cent c.i. −11⋅9 to −6⋅9) per cent; P < 0⋅001), but the relationship was reversed in low-HDI countries (+12⋅1 (+7⋅0 to +17⋅3) per cent; P < 0⋅001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0⋅60, 0⋅50 to 0⋅73; P < 0⋅001). The greatest absolute benefit was seen for emergency surgery in low-and middle-HDI countries. Conclusion: Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries
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